1. Field of the Invention
The invention relates to a gas discharge display device having a space filled with gas, which is subdivided into a gas discharge space and a post-acceleration space by a control plate provided with electrode strips (column and anode row conductors) which form a matrix, a fluorescent screen on a front plate which bounds the post-acceleration space and is provided with an anode layer, one or more surface cathodes on the inside of a back plate which are insulated from each other and which bound the gas discharge space, and an auxiliary control plate, which is provided with anode conductor strips, on at least one side, which are aligned parallel with the anode row conductors.
2. Description of the Prior Art
It was well known, heretofore, that, in a gas discharge display device a reduction of the number of drive switching circuits is possible by combining the anode row conductors into groups combined with a subdivision of the cathode into cathode strips that are parallel with the anode row conductors and wherein each cathode strip corresponds with a group of anode row conductors.
The use of such combination of group selection, with a subdivision of the cathode into strips parallel to the anode row conductors does not completely ensure the flow of cathode current to only the desired anode row conductor. Rather, in most cases, a very small fraction of the current also reaches other anode row conductors in the same group as the selected anode row conductor. This results in the other anode row conductors also being weakly illuminated in addition to the selected anode row conductor.
In copending application Ser. No. 470,702 filed Feb. 28, 1983, and now abandoned, of which I am a coinventor, the function of a row-wise constructed tetrode grid for reducing column crosstalk was described. Such a construction is realized by an auxiliary control plate with selectively one or two additional potential surfaces separated from one another, the auxiliary control plate being provided on at least one side thereof with anode conductor strip lines conducting the electric current and aligned parallel to the row conductors of the control plate, the strip lines having a passing or a blocking potential selectively applicable thereto for the electrons flying in direction towards a luminescent or fluorescent screen.
Gas discharge display devices of this general type are described in U.S. Pat. No. 4,130,778, DC PDP with Divided Cathode.
In a gas discharge display device (flat viewing screen) the plasma is advanced stepwise from one anode row conductor to the next anode row conductor. Just as many anode row conductor drive circuits are required as the number of anode row conductors that are present in the display device.